The invention relates to orthoses useful for the rehabilitation of patients with injured joints, weakened joints, and/or neurological deficits degrading motor control or operation of joints. More particularly, the invention relates to instrumented orthoses for the performance of monitored rehabilitative exercises.
Both muscles and bones should be exercised to maintain strength. Also, bone fractures that are exposed to permissible weight bearing stress often heal more predictably and more rapidly than fractures that are not stressed at all. Improved healing based on application of appropriate stress is also believed to be true for connective tissue, such as ligaments and cartilage.
In the case of neurological injury or degradation, the nerve impulse pathways that control skeletal motor functions and joints are interrupted due to loss of brain cells or nerve conducting structures. Such neurological injuries can result from cerebrovascular accidents such as ischemic or hemorrhagic strokes or certain types of head trauma. Recovery mechanisms involve creation of new neurological pathways by retraining the motor functions with different surviving brain cells as receptors. This requires physical therapy and joint exercise very similar to exercise that is advantageous for rehabilitation of joints following orthopedic injury. Additionally, joint disuse following such neurological injury similarly requires orthopedic rehabilitation and stress to effect useful recovery, given the secondary orthopedic damage resulting from the disuse.
Suitable stress can be applied to the tissue by the performance of selected exercises. For example, isometric exercises generally involves the exertion of force against a relatively immovable object. To perform isometric exercises, a restraining device can be used that has a substantially unchanging position for the duration of a particular exercise routine. Isotonic exercises involve exertion against the same weight or resistance through a range of motion. Isokinetic exercise is designed to mimic exertions that take place on a playing field or the like. When performing isokinetic exercises in a simulated environment, a machine is used to provide resistance in direct proportion to the exertion of the exerciser.
Isometric exercises are particularly useful with painful injuries to lower the risk of further injury. If performed in a controlled manner, isometric exercises can be performed earlier in the recuperation period to speed recovery. As the patient's recovery progresses, isotonic exercises or other exercises can be used to reestablish a desired range of motion about a joint. With continuing recovery, eventually the patient is able to perform a full range of exercises.
A difficulty with the application of stress to an injured joint is that the application of excessive stress can further injure the joint rather than assist with the healing. Thus, the exercises need to be carefully planned to provide appropriate amounts of stress. Also, the performance of the exercises should be monitored closely by a physician, physical therapist or other appropriate health care professional to optimize the treatment and to reduce the risk of injury. The need to carefully plan and closely monitor the exercises provides a cost and motivation barrier to accessing desirable amounts of exercise.